The present disclosure relates generally to temporary insulating connectors, also referred to as temporary “touch-proof” connectors for coupling with lead connector elements of medical leads extending percutaneously into a patient's body, and more particularly to temporary touch-proof connectors that shield the lead connector elements from making contact with earth or potentially hazardous voltages when not in use.
Unipolar and bipolar surgically implanted temporary heart wires and temporary leads and nerve, organ, and muscle stimulation leads or wires are well known in the art, some examples of which may be found in the issued U.S. patents listed in Table I below.
TABLE IU.S. Pat. No.Title3,035,583Conductive Sutures3,125,095Flexible Stainless Steel Sutures3,244,174Body Implantable Conductor3,416,533Conductive Catheter3,664,347Electric Heart Stimulation Method and Electrode3,949,756Sutures with Notch Near Needle-Suture Junction4,010,756Heart Pacer Lead Wire with Break-Away Needle4,054,144Short-Crimp Surgical Needle4,338,947Positive Fixation Heart Wire4,341,226Temporary Lead with Insertion Tool4,442,840Electrical Connector Apparatus and Method for aTemporary Cardiac Pacing Wire4,444,207Method of Anchoring a Temporary Cardiac Pacing Lead4,530,368Temporary Bipolar Pacing Lead4,541,440Bipolar Epicardial Temporary Pacing Lead4,553,554Electrical Lead and Method for Temporary CardiacPacing4,630,617Heart Pacer Lead Wire with Pull-Away Needle4,633,880Surgical Electrode4,693,258Surgical Electrode for Cardiac Pacing and Monitoring4,972,833Epicardial Pacing Lead5,217,027Temporary Cardiac Lead5,241,957Bipolar Temporary Pacing Lead and Connector andPermanent Bipolar Nerve Wire5,314,463Bipolar Nerve Electrode5,334,045Universal Cable Connector for Temporarily ConnectingImplantable Leads and Implantable Medical Devices witha Non-Implantable System Analyzer5,350,419Cardiac Pacing Lead5,423,876Intramuscular Lead Having Improved Insertion5,557,210Universal Cable Connector for Temporarily ConnectingImplantable Stimulation Leads and Implantable MedicalDevices with a Non-Implantable System Analyzer5,679,022Universal Cable Connector for Temporarily ConnectingImplantable Stimulation Leads and Implantable MedicalDevices with a Non-Implantable System Analyzer5,782,892Medical Lead Adaptor for External Medical Device5,792,217Temporary Bipolar Heart Wire5,871,528Temporary Bipolar Heart Wire5,931,861Medical Lead Adaptor Having Rotatable Locking ClipMechanism6,397,108Safety Adaptor for Temporary Medical Leads
All patents listed in Table I are hereby incorporated by reference herein in their respective entireties. Certain of the patents listed in Table I disclose surgically implanted temporary heart wires or leads for use with an external unipolar or bipolar cardiac pacemaker and/or monitor or pacing system analyzer (PSA) in a manner that is well known in the medical field. As described further below, temporary heart wires are implanted in a patient's body to extend between a heart chamber through a percutaneous incision to an external medical device and are removed after a time. Heart wires are sometimes alternatively referred to as temporary pacing leads but are distinguished from endocardial temporary pacing leads that are passed percutaneously through an incision into a vein and transvenously advanced into a heart chamber, typically employing a removable stiffening stylet, as disclosed in the above-referenced, commonly assigned '861 and '892 patents. Such endocardial temporary pacing leads are implanted and used for closed-chest temporary pacing and monitoring of a patient's heart in a variety of single and dual chamber pacing modes. When their use is terminated, they are retracted through the transvenous route, and the incision is closed.
Unipolar heart wires, e.g., the Medtronic® Model 6491, Model 6492, Model 6494, and Model 6500 Temporary Pacing Leads, and bipolar heart wires, e.g., the Medtronic® Model 6495 (J-2M) Temporary Pacing Lead, are shown in the above-referenced, commonly assigned '463, '217 and '328 patents. Such unipolar and bipolar heart wires are implanted in the course, preferably at the end, of a surgical procedure where the heart is surgically exposed, e.g., to provide post-surgical temporary pacing and monitoring, and are withdrawn through a percutaneous incision by applied traction when their use is to be terminated.
The elongated unipolar and bipolar heart wire bodies are constructed of a single conductor or two conductors, each conductor comprising a number of fine, stainless steel wires twisted together to form a single, flexible, multifilament wire. The major portion of each such conductor within the wire body is typically insulated with a polyethylene, polytetrafluoroethylene, silicone, nylon, or other suitable electrically non-conductive and bio-compatible materials to insulate the wires from one another (in bipolar versions) and from the environment. A short length of each such conductor at the distal end of the heart wire body is exposed to act as a pace/sense electrode when passed into the myocardium. The distal end of the most distal electrode is axially coupled to an elongated retention coil that in turn is coupled axially by a severable, non-conductive, filament to a fine, curved surgical needle.
The fixation into the myocardium is accomplished with the heart exposed by using the curved needle to pierce the epicardium and to draw the pace/sense electrode(s) and retention coil through a portion of the myocardium without penetrating all the way through the myocardium and into a heart chamber or blood vessel. In this process, the needle is passed back out through the epicardium, and the filament coupling the needle with the fixation coil is severed after electrical testing is completed.
A tubular lead connector element is formed at the proximal end of the heart wire body and electrically connected to each insulated wire in an in-line configuration. A straight, Keith-type, cutting needle extends proximally from the proximal end of the most proximal lead connector element and is used to pierce the thoracic wall to extend the proximal portion of the heart wire body outside the body when the surgical incision accessing the heart is closed. Then, the Keith-type needle is typically clipped or broken off, and each heart wire connector element is coupled to an external medical device.
A similar nerve stimulation wire and procedure of implantation is disclosed in the above-referenced, commonly assigned, '463, '217 and '328 patents.
The proximal connector elements of such temporary endocardial pacing leads and heart wires are typically coupled to terminals of external pacemaker pulse generators, e.g., the Medtronic® Model 5348 and 5388 single chamber or dual chamber pacemaker pulse generators or similar devices which are available on the market. Other suitable connections are also considered, for example if the lead length is short, by using an extension cable which terminates in the external pacemaker pulse generator. A direct connection may be made if the lead or wire connector elements are compatible with the external medical device connector terminals and if the lead or wire body is long enough. In certain situations, the connector elements are not coupled to terminals of pulse generators and thus the pacing leads and heart wires are coiled up and positioned for future use, for example by being taped to a patient's chest. When not coupled to terminals of a pulse generator, temporary touch-proof connectors are used so as to prevent connector elements from contacting earth or hazardous voltages.
Concerns relating to the safety of leaving any lead connector element exposed have been voiced by regulatory agencies over many years. It is dangerous to a patient to conduct electrical current or static electricity through a lead into a patient's body, particularly through a temporary pacing lead or heart wire attached to the heart. Connector regulations IEC 60601-1 dictate that medical leads shall be constructed in such a way that no conductive part or surface of a connector element in the part of the medical lead remote from the patient can contact earth or possibly hazardous voltages. Moreover, regulations IEC 60601-1 and 60601-2-31 including amendment 1 requires connections to a patient be equipped with touch-proof connectors that can only be implemented by industrial manufacturing.